In recent years, liquid crystal displays (Liquid Crystal Display, LCD for short) have been developing by leaps and bounds, and are widely applied in fields such as smartphones, industrial meters, and medical instruments, bringing richer visual enjoyment to users.
However, an LCD is a passive light-emitting display, whose display effect is greatly related to LCD backlight brightness and ambient luminance. For example, backlight brightness of an LCD in the sun must be adjusted to a very high level to ensure that the LCD presents clear display content; inside a dark place, the LCD may present clear display content only by maintaining a relatively low level of backlight brightness of the LCD.
To ensure that an LCD can still present clear display content when ambient luminance changes, methods of light adaptive brightness control (Light Adaptive Brightness Control, LABC for short) and content adaptive brightness control (Content Adaptive Brightness Control, CABC for short) are proposed in the prior art.
Exemplarily, in the LABC method, after an electronic device is turned on, an application processor (Application Processor, AP for short) first checks ambient luminance, then obtains through calculation current LCD backlight brightness according to the ambient luminance, and transmits to an LCD driver circuit the LCD backlight brightness obtained through calculation. In this way, the LCD driver circuit can output a pulse width modulation (Pulse Width Modulation, PWM for short) signal to a backlight driver module, so that the current LCD backlight brightness can be adjusted. If the ambient luminance exceeds a particular range, the electronic device starts the foregoing process again to re-adjust the LCD backlight brightness.
However, in the current LABC method, LCD backlight cannot track ambient light changes in real time. As shown in FIG. 1, there is much blank space between a straight line indicating LCD backlight brightness and a curve indicating ambient luminance, where the blank space indicates wasted energy. In addition, because a PWM signal output by an LCD driver circuit is not highly precise, 8 bits generally, a sudden backlight change occurs when the LCD backlight brightness changes. As a result, a user sees obvious flickering in a light adjustment process.